question marks on some applications in dock. URGENT!

Hi, when i opened my macbook today, i noticed that when i clicked on mail, there was ablack question mark over it, then i tried to open photo booth and aperture but the same thing happened, safari, itunes, pages and some other apps are working but some aren't. i verified and repaired disk permissions and searched for the broken apps in the finder but they're not there. please help...

If the applications appear with a question mark in the Dock, it means that the application has either been removed or moved to a different location. Can you give us a list of the applications that have since been removed/moved? It's likely that you may have to reinstall them.

Question marks in the dock indicate that the path to the application can not be found. You said you searched for the missing apps in Finder. Did you check the Applications folder? Look in the Applications folder to see if those apps which show the question mark in the dock are there. If they are, re-create the shortcuts in the dock. If they're not in the Applications folder, they may have been deleted or moved.